Process of converting crude iron into malleable iron or steel



3 Sheets-Sheet 1 L. "88888.5?.V

@if CONN-mmm URUDE IRON INTG'MALLEABLE IRON 0R STEEL.

atented Een. Z5, 1888.

(En Model.) -3 sheetssheen z. I

E Gr. L. ROBERT. PROCESS 0E GONVEETNGHCEQUDE IRONINTO MALLEAELE IRON 0E STEEL. No. 895,175. Patented 1360.25, 1888..

(No Mdel.) 3 SheetS-Sheet 3.

G. L. ROBERT.

PROCESS 0F CONVERTING GRUDB MoN-INTO MALL-BABE IRUN 0B. STEEL.

No. 395,175. Patented Dec. 25, 1888.

@wwwa/.aow I SWU. @Micra :PECIEECATIGN forming part of Letters Fatemi lilo. 395,135, dated Iileeember 25, 188B.

'lipplstion iilad lcvemher le, l. Sensi En. 290,778. (No specimens.) Entente-cl in England h'iay 9, 1888, No. 6,888.

To all when@ i mag' concern;

Be it known that. l, GUsTAVE LOUIS ROB\ Em, n citizen oi' the Republic el n rence, re siding at Stenay, Department ot the Meuse,

Republic of France, have invented e new and useful improvement in the `irocess of Con vert-ing Lrude iron into Mnlleeble Iron or Steel, (for which vl have obtained paient in England, No. (3,886, May i), 1888,) of which the following is n full, cles-r, and exa-et speciica tion.

In the conversion of crude or pig iron into malleable iron .or steel by the use of nir or oxidizing agent in en seriform state for the purpose of oxidizing the combustible elements held in combination with the iron sew eral fundamental conditions underlie end are tion o all the comlmstible elements held by the iron; secondly, it is importent that -the airshzill come in Contact. with the metal in such nin-nner that the eliminated impurities may not. be caused to pass through the body of the inet-nl to any nniterial extent, and that when eliminatedthey simil remain ns fer as possible in n state of peru-mirent separation from the metal; thiwlly, it is of the greatest moult-nt that the nxnnuer of bringing' the :tir in conta-ct with the iron shall be such that the elements of the iron shallbe thoroughly oxidized while the nir is :is completely deoxidized as possible, in order that the smallest quant-ity consistent Vwith rapid' conversion :ind thorough conilmstion may. be employed; fourthly, it is most desirable that :thigh temperature be maintained and the metal be brought to an extremely Huid condition without the use-of nnyo'ther fuel than that aff forded by the combustible elements of the iron, and this is necessary in order to nroduce andV maintain' the highest possible teme `peinture in the metzib which results in greater fluidity. Some of these requisites have long been known to those skilled in the art, and with the view of meeting them inventors have heretofore, not unilaterally, adopted the pre@ tice of forcing the sir through or into the interiorof the body ofi metal, the general understanding of the requirements being that the intimate commingling of the -sir and the metal was otl advantage in producing the re quired result.. lilith this View they introduced the blast vertically through `the bottoni of the converter or horizontellyv into the body of the metal, or from above obliquely, but in all cases et aconsiderable depth below thev normal surface of the metal, so as topene- .trete the mess of metal in Isuch manner 'that s portion of the met-sl throughout theoperation of conversion was always above the ail blast or current.

In order io more clearly explain the dierent effects which result from these different modes of applying the blast, I have appended .diagrams in which l have attempt-ed. to indicate roughly what may be imagined to take place in a converter during such processes. The diagrams are all supposed to representa. vertical section of the meta-l in s converter, Figure l showing the blast introduced vertiesllyat the bottom, Fig. showing it intro yduced horizontally at or close to the bottom,

and Fig. 3 showing it introduced ecol' near the top, out directed into the body of the metal.

In Fig. l the air is shown ascending through the whole body of the metal, causing violent eb ulb' tion and disturbance, everywhere throwing up the metal end impurities high above the surface, to which they full back again, the arrows showing the return-currents bringing down the scorie. to be again subjected to the pounding effects oi.' the blast, and the impurities being `driven into the body of the metal.

In Fig. 2 blasts are shown entering from opposite sides of the convert-er, and although these will not cause such violent disturbances as in Fig. l, it will nevertheless be seen that the air permeates the gresierpart of the metal and that the return-currents from the surface dra-g down the scorie into the mass of' the metal. This blast also being at ai high pressureceuses very violent disturbances of the whole mass, so that the scorie'l cannot remain quiescent st any one point.

In Fig. 3 the' blast enters nem' the surface, and itis driven at once into the meta-l, with the res ult that violent agitation of the greater part IOO of the whole mass tal-:es place and the scorie is formed in the metal, 4and after it rises to the surface it is again and again carried and forced down into the metal.

In all of these processes Where the air onters and traverses the body oi molten metal it is necessary to employ a powerful blast, 'using heavy and expensive machinery, and the air, afterithas passed into the metal, tends to force the particles'oi the' latter apart and ascend to the surface in great bubbles, so ,that comparatively limited areas of metal are subjected'to the action of the oxidizing agent, While the silicon, carbon, and other ooinbus ble elements are not brought into that intimate Contact with the oxidizing agent which is essentialto insure the most complete, rapid,

and uniform combustion, and. tbe force of the air-current and the great expansive action of the 4air as it escapes' from the surface of the bath produce both at the surface and in the body of the metal violent currents and vortices, while the descent of A the metal thrown upward by the action of thc'blast increases the agitation of the metal, so that the eliminated impurities are. intimately mixed with and car ried about in the bat-h by the powerful enrrents, and are returned again and again to the mouth of the tuyere and exposed to the poundingl effects of the blast and driven back into the body of the metal.

yln consequence of the necessity' et maintainingr` a high pressure of the blast in .order to give the necessary penetrating effect into and through the molten metal, the amount oi' ,oxygen supplied to the metal toward the completion of the conversion when moet of tile' combustible elements have'been. removed is m excess of what is actually required, and the utmost care 'is required to ont off the blast in such manner as'to secure the desired converting eieet without overoxidizing the iron.

A further objection incident to the abovespecified modes of conversion results from the fact that the highlyncompressed air is richer 'in oxygen the instant when it enters the bath than during its subsequent progress, and natn `11i-ally causes unequal oxidation, the oxidation being excessive and evenV destructive near the mouth of the tuyere and deficient at or near the surface of the metal, where the air by expansion has resumed its natural volume, and as the point of rapid and greatest conversion is nearest the bottom of the bath,

and as the greatest amount of impurities are' eliminated at this point, they must .traverse the entirey body of the 'metal before reaching the surface. -This objectionable effect increases in degree as the combustible elements of the iron are burned out, so that asthe process of conversion approaches completion the danger of over oxidizing the iron greatly increases. It is not possible, therefore, by any of the above-named processes to maintain that constant relation between the metal and the con verting agent necessary to produce a uniform -and determinate qui'ility of metal, and the essere process and the product are iiti'ul and irregulan y I 1 it is the object of my invention to avoidie unstable and involved conditions producing the variable, uncertain, and impcrfectresults heretofore spe'ciiied 'and to establish conditions which are normally fixed, constant, and

regular, ivliile capable of being varied, adjusted., or inodiiied, at tile will otf the operator,

vaccording to those variations in the conditions-which result as the process of conversion is carried onward toward completion. In effecting these results l take advantage of a Well-i-:liown law of physics, that a 'violent .atomic agitation ot' a liquid holding parti-cles in suspension, or of a mixture of solid or seniiwolid and iinid matters, will favor the sepfuation` of the mixed materials; but as suoli a violent agitation of the entire masso metal in a converter at once would not be practicable, and it would, moreover, be attended with tbe disadvantages before re terred 'to oi remixing the particles of impurities with and among the particles from which they have been separated, and from which tbey should be maintained in a sepfaratcd state, lv

' bart from the methods heretofore ein lo 'ed of acting upon substantially the entire body of metal at one time and subject limited portions only at a time to violent agitation and to the action off the oxidizing or converting agent, maintaining the greater `port-ion in a comparatively quiet state', but bringing every portion repeatedly within the area of violent agitation. It will therefore be evident that one of lthe primary.characteristics of my process is that 'the body of molten metal .is divided during tbe operation of converting los practically into ltwo sections or portions in radically different condi-tions. @ne section is 'small in volume and tlieparticles thereof aresubjected to violent atomic action-albania this portion is violently agitated and atom-v ized or broken up into small particlesand as a result the impurities separate. themselves from the metal, while the other portion, comp prising the greater body, is comparatively quiescent and free from violent commotions.

The greater violence of the action tliaftisl practicable to impart to limited portions of the ineinl results in a twofold effect. First, it favors rapid conversion, because such violent action separates and finely divides or atoinizes the limited portions acted upon at one time, exposing large areas of surface to the converting,` agent; second, it secures the separa-tion of the impurities by the natural action before referred to, whether these impurities were in the crude metal orare formed in the bath during' the process of conversion;v and, third, it carries the particles of metal away from the area of violent agitation and conversion, so as to avoid continuous action of the oxidizingag'ent on the same particles' yand brings in new metal to the agitating and ccnvger-ting area, thus prevent-ing over-oxidation.

As one means of securing A the desired zone of conversion in suoli exact quantities`l as villy maintain the lproportion ofi-lie metal acted on relative tothe volume of air as is '15 necessary to the production of the best resuits. The raising of the level-of thcinetal l could be effected by adding more metal. or by vmeans or a false bottom, which would raise the Whole of the metal orctlierwise, so as by 2o occupyin' part of the space previously occui pied by tile metal to restore the surface-level.

j l Will new describe apparatus which may be used incarrying out the foregoing process; but I wish it to be 'understood that l do .c5 *not limit myself to the'use of this apparatus,

which forms-the subj ectof an application for.

a patent iiled' by nie August 3G, i887, Serial No. 248,578.

Figs 5 and' show, respectively, a vertical go section and a horizontal sect-ion, the latter through linesfl 2 3 4.- 'oi lone of the arrangements, while Figs? and 8 showin the same manner another arrangement of my converter. Fig. 9 is a sectional view of a tuyure.

*35"'ln Figs. 5 and 6 the converter, the cross-section of which. is rectangular 'and has its corners rounded, receives a swinging motion on tbc journals A and A', supported by pedestais.

.an of any ,mechanism sncl'll as that, used for the manipulation ci' oscillating converters.

The tuyeres o., through which 'the blast is iotroducsd,l are arranged .in a straight line, w

,-y, on. one side, l), onlyV of the converter, and

si; they open intova box or chamber, 0 into which the blast enters through a supply-pipe, This box is provided with sliding 'glazed sighoholes fb, preferably the same in number as there .are tuycres a, whereby the state of 5o the' toy-eres can be Watched during the opera'- tion, and whereby, also, they can be cleaned or replaced with' ease, and through which `lime or otherl reagent .can be inserted if re- The side,`?, chosen for the application of the tuyeres yis preferably one presenting the greatest surface to the metal, and the plane in which the tuyeres are formed is parallel to surface of metal 'andto the. axis of rotation, A' oo A2531? 'the converter, so. that Whatever the inelig- This motion can be obtained by means sesgo' posed, 'as before, on a horizontalline in plane parallel to the axis of the apparatus; The

' placing of all the tuyeres in one horizontal line parallel with the swinging axis enables the operator to maintain the proper relations between the tuyeres and the surface of the metal, and at anytime to stop the operation almostv instantaneously by simultaneously freeing all the tuyeres from'. the molten metal, this being done by turning the converter upon its trunnions. i

The tnyeres placed thus horizontally form, with the straight face P, onto' which they open, unequal angles, (see Fig. 8,) the magnitude of which varies with the form given to the crosssection of the apparatus, :The object of this arrangement of the tuyeies is to facilitate the 'iinpartingofa gyratcry motion to the metal in fusion, which motion exposes the molecules of metal successively to the v oxidizing action of the lblast at the surface of the fused metal. By'placing` the tuyeres' at diicrent angles the lhonizontal rotary motion is prevented from 'becoming too violent, the' impulse iinparted by the blasts from the tuyeres having the greatest inclination being partially counteracted by those havingT less,- these latter tending to blow the metal and scoria more roo 'directly across to the opposite side'ofthe converter. 'Bythis means and the circunh stance that all'the tuyeres are in one horizontal line 'a comparatively feeble blast sind an immersion of the tuyeres inv the metal lslightly below its nominal level are suiicient to oxidize the mass, and the reaction takesy place at or near the surface.

The products'of the reaction are therefore transmitted at once to the slag, instead of act ing on the metal and the lining of the conf verter below. l

l may subject successive limited portions of the entire bath to the action of lthe con- IIO v'erting agent without imparting'a gyratory motion to the body of metal, in which case othermeanso feeding it to the area of conf kdescribed for securing the simultaneous conversion and violent local atomic agitation of the metal, nor to the specific construction of apparatus orarrangement of parts shown forcarrying out said process, as this may be izo done with various means in different Ways, as

will be evident to those skilled in the art.

` l do not herein claim the specific features described 'and clained .in .my applications filed November i9, 1888., bearing Serial Nos. 291,189 and 291,190, l *f What vI claim is-f- 1.` The within-described improvement in.

converting erode iron into' alleable ironuor 'Sesma e steel, consisting in imparting to limited portione in succession of e beth of molten metl- V violent agitation in the presence of e converting agent, separating the impurities and the metal, returning the latter to the body of the metal in the beth 'and back from the boy of' metal in the beth to the aree of agitation, and repeating these operations until all the metal has been acted on, the impurities are separated therefrom, en@ the conversion is complete, substmit-ially as set forth.

2, The 'process ofconverting crude iron into malleable iron or steel, which consists in impar-ting to successive limited portions of e, bath of molten metal e violent atomic agitation and separating the metal and the impuri-ties, returning the metal to the body of the bath and maintaining the eliminated impurities in their seperated State, and repeating these operations" until the entire body has been repeetedlv operated 11poi1,substa1itially,

as set forth.

In testimony l whereof l have signed my. 11a-me to this specification in'I the presence of tfwo subscribing witnesses.

' GUSTAVE L. HUBERT.

Witesses:

F. L. FREIMAN, A. E.' T. HANSMANN. 

